In FF,moving anchors will create more anchor after swaping text to html

Description

1.Insert an anchor.
2.Move it by mouse click and dragging.
3.Swap text to HTML mode, then back to text mode.
4.All above will make as many anchors as the times you moved the anchor. It looks like copy not just a move.

The test environment is FireFox3.5 and the Xinha on-line demo.
BTW, insert anchor doesn't work for IE7.(another ticket has already mentioned this)

(This is rain in the discussion forum, I can't log in the ticket system with that account. So these two system need different account?)